Study reveals new molecular properties of water

Water is known as an efficient transporter of its autoionization components — the charged particles, protons and hydroxide ions, created when an H2O molecule splits.

Until recently, scientists assumed autoionization transportation occurred through a single mechanism, dictated by a single variable, the direction of the involved hydrogen bond.

New theoretical modeling, however, showed the transportation mechanism features a fundamental asymmetry. But scientists have struggled to demonstrate the predicted asymmetry in the lab.

Scientists at New York University devised a new experiment to illuminate the mechanism’s asymmetry.

Researchers cooled water to four degrees Celsius, the temperature of maximum density. The increase in density highlighted the differences in ion transportation when imaged using nuclear magnetic resonance.

Hydrogen atoms are relatively free to move from one water molecule to another, which allows for the fluid transportation of water’s charged particles. When researchers cooled water to maximum density, they altered the speed at which hydrogen atoms hopped from one molecule to another.

“The study of water’s molecular properties is of intense interest due to its central role in enabling physiological processes and its ubiquitous nature,” NYU professor Alexej Jerschow said in a news release. “The new finding is quite surprising and may enable deeper understanding of water’s properties as well as its role as a fluid in many of nature’s phenomena.”

“It is gratifying to have this clear piece of experimental evidence confirm our earlier predictions,” said Mark Tuckerman, a professor of chemistry and mathematics at NYU. “We are currently seeking new ways to exploit the asymmetry … to design new materials for clean energy applications, and knowing that we are starting with a correct model it central to our continued progress.”